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Open-source runtime system for component-based implementation of automation solutions with Java
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/**
 * PROJECT   : Elbfisch - java process automation controller (jPac)
 * MODULE    : ExclusiveDisjunctiveEvent.java
 * VERSION   : -
 * DATE      : -
 * PURPOSE   : 
 * AUTHOR    : Bernd Schuster, MSK Gesellschaft fuer Automatisierung mbH, Schenefeld
 * REMARKS   : -
 * CHANGES   : CH#n   
 *
 * This file is part of the jPac process automation controller.
 * jPac is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * jPac is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with the jPac If not, see .
 */

package org.jpac;

import java.util.Iterator;
import java.util.ArrayList;

/**
 * used to combine a number events in a exclusive disjunctive way. It is fired, if "process event 1" XOR "process event 2" XOR .... are fired
 * @author berndschuster
 */

public class ExclusiveDisjunctiveEvent extends ProcessEvent{
    private ArrayList combinedEvents;
    Iterator       eventIterator;

    public ExclusiveDisjunctiveEvent(ProcessEvent anEvent){
        combinedEvents = new ArrayList(10);
        combinedEvents.add(anEvent);
    }
    
    @Override
    public ExclusiveDisjunctiveEvent xor(ProcessEvent anEvent){
        combinedEvents.add(anEvent);
        return this;
    }

    @Override
    public void reset(){
        //reset own context
        super.reset();
        //reset all conjunctive events
        Iterator e = combinedEvents.iterator();
        while(e.hasNext()){
            e.next().reset();
        }

    }

    @Override
    public boolean fire() throws ProcessException {
        int     fireCnt  = 0;
        boolean IamFired = false;
        eventIterator = combinedEvents.iterator();
        //give all events the chance to fire
        while(eventIterator.hasNext()){
            if (eventIterator.next().evaluateFiredCondition()){
                fireCnt++;
            }
        }
        IamFired = fireCnt == 1;
        if (!IamFired){
            //reset all events, which are fired in this cycle, if it is not exactly one
            eventIterator = combinedEvents.iterator();
            while(eventIterator.hasNext()){
                ProcessEvent event = eventIterator.next();
                if (event.isFired()){
                    event.reset();
                }
            }
        }
        return IamFired;
    }

    @Override
    public String toString(){
        String  eventList = "";
        String  firedStr  = "";
        ProcessEvent e    = null;
        eventIterator = combinedEvents.iterator();
        if (eventIterator.hasNext()){
            e         = eventIterator.next();
            firedStr  = e.isFired() ? "[fired !]" : "";
            eventList = e.toString() + firedStr;
        }
        while(eventIterator.hasNext()){
            e         = eventIterator.next();
            firedStr  = e.isFired() ? "[fired !]" : "";
            eventList = eventList + " xor " + e.toString() + firedStr;
        }
        return eventList;
    }

}